System of control



Sept. 13, 1927. 1,642,028

- H. H. JOHNSTON SYSTEM OF CONTROL I Filed Dec. 50, 1920- WITNESSES: INVENTOR gggm) Howard/ ud Patented Sept. 13, 1927. I

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HOWARD mimsmoa, 0F EDGEwooD; rmxmsYiiVANIi, hesitation To House ELECTRIC 6: MANUFACTURING COMPLKN-Y; A coRr'oRA'rIoN or rEN'NsYfi- VAN IA.

a smear common;

ih iiili cation filed December 330, Serial'fio; 434,0?6,

/ intention riaaste iiiotor-control' Sysrailw'ay r U I The object of my nvention is to provide aii oterldatl relay k having simple means for the Value at which itofiei'ates to" meet varyirl requirements k v A A Int'h'e present system it 1s proposed toso utilize the reset magnet of an overloadieia that it may, in addition, to its no malfi heuoiiappsi-ate tfcbppbg e theactuation of th'er'elay by; the joiferloadnianet. In normal operatibii, the reset magnet; is energized only to restore the relay lto its inltial' operat ve position. case" it therelay operate at value abovethe normal value,

which Figure 1 isa side elevational ovehb'aaaiaystruc ure; t v a 2 is it iew, iii" elevation, of the reset mechanism; and t V a Fig. 3 is; a: diagrammatic View of circuits and apparatus embodying my inyention. Rrertmgm Fig. 1', an overload relay: is

p rov ided with a stationary core member. Lano erating coil Qxaiidjan armature 3.1 A

v anger 4 is maimed a esha-many with the co'i-e" member 1. Contact discs 5 4 6 nors many engagestationary contact members afid 8respectiyely, when thearmature 3 is in its'lower position and aredisengaged when the armature is up The armature 3 is latched its upper position by. a trigger tlg,

A resetinaghiet 11 is pro i ide'd with an armature 12 for operatingthe trigger 'llhe reset magnet 11 also controlstheactuation of thearh'iat'ure 8. An adjusting screw 10 acts as a' stop or'rest' ;t'or armature 3" and also te'riis' and it lias particular relation to systems as are employed 111 connection with M tiofii: with the a oln anyifig. drawings, in

ser ves to determine the initial air gap betweencore nember 1 and the armature.

In orderto restriotthe operation-of thea'r -c mature 3iby the actuating 'coil 2 one end of thecore l-ltpofthe reset magnet is extended to form' apple piece 117), theupper face of which is disposed to liesubstantially parallel-with a face 3a providedon t'he armature 3, when the latter is in its lower position; As shown, a bracket 10a iscarried" by the other endof the core 116;; Therefore; as will be observed the reset magnet 11:, with the pole piece llcand bracket 11b; simulates a horse shoemagnet, which, with the armature 3 in the posit-ion shown-in dottedlines in Fig. 1, forms asubstantially closed'ma'gnetic circuit. Accordingly, when the magnet 11 is energized, it; will oppose the operation of the armature 3 by the actuatiiigcoil 2. I

The relay may be set to operateat' either of two; predetermined .mot or curi'ent values.

,The relay may be connected as shown iii 3,- w-liereintheoperating coil 2 is cir-' cuit with a ihotor armature 25 andthe usual master controller 252i The operating coil 31 of amain -line contactor is controlled by ijelay contact members 5 and 7, which members are normally in engagement, b controller contact members '27 and 28; whic neng'age'on all running points of thecohtroller, andflb'y CQIitlQljSWltCh 16 which is normally positionedto the-left, as viewed" in'thefdraw'ing. A: snap switch 13 completes a circuit coniprisingreset magnet coil 14, aresistor' 19 and thenormally closed" relay contact members-6 and 8 another circuit for this coil is stablished when switch 16 is actuated to the right. I a I Assunfii ig a railway car operatingon a fairly level track, snap switch 13'i's op'en a'nfd the relay setting is fixed: by the adjusting screw- 1 0; It is also assumed thattheoperat} ing; coil 2 is properly designed fora known rangef of' current values; The relay will be actuated to dropj'iout linecontac't'or 31 by t'h' separationof coiitactmem' bers 5 and? in casethfemjotor current rises above a p'red'g termed value, forlanyreason; such as too rapid acceleration of the motor. A circuit for the line contactor extends from positive line conductor 15, through control switch 16, when actuated to the left, contact members 27 and 28, conductor 29, relay contact members 5 and 7 and line contactor coil 31, to the negative line conductor 21. Switch 16 is actuated to restore the relay setting, as will be set forth later.

It is desirable on heavy grades, to raise the setting of the overload relay and this is accomplished by means of the switch 13, shown in Fig. 3. A circuit comprising the coil 14 of the reset magnet 11 extends from the positive line conductor 15, through the control switch 16, when the latter is in its left-hand position, conductor 17 switch 13, interlock contact members 6 and 8, resistor 19 and coil 14, to the negative conductor 21. The adjustable resistor 19 determines the degree of energization of the magnet 11.

The main motor circuit extends from trolley conductor 15, through controller 22, conductor, 23, overload relay coil 2 and motor armature 25 to the ground. I'Vhen the circuits, as traced, are energized, coils 14 and 2 exert opposing forces upon the relay armature 3. The armature 3 operates upon the occurrence of a predetermined overload value of the current traversing the motor circuit. The plunger 4 is lifted by the armature3 to disengage the interlock members 6 and 8 and thereby open the circuit of coil 14.

After the overload relay has operated, it may be restored by actuating the control switch 16 to the right to establish a circuit from the positive line conductor 15, through the control switch 16, conductor 26, resistor 19 and coil 14 to the negative line conductor 21. Armature 12 is attracted by the magnet 14 and causes the trigger 9 to disengage armature 3, which resumes its initial position, indicated by dotted lines.

After the car has passed over the grade, switch 13 is opened and coil 14 is no longer energized.

It is evident that I have disclosed a simple overload mechanism capable of operation under both normal and abnormal conditions and have eliminated the necessity of manual 1y adjusting the overload mechanism. I have also made use of the necessary reset magnet to accomplish the desired results without materially adding to the cost or complicating the relay construction.

I claim as my invention:

1. In control apparatus, in combination, a contact member disposed for movement, a coil for actuating the contact member,-said coil being adapted to function when energized by a predetermined current, means for locking the contact member in a predetermined position, means for releasing the contact member and means for utilizing the releasing means to oppose the actuation of the contact member by said coil.

2. In control apparatus, in combination, a contact member disposed for movement, a coil for actuating the contact member, said coil being adapted to function when energized by a predetermined current, means for locking the contact member in a predetermined position, means for releasing the contact member and means for utilizing the releasing means to oppose the actuation of the contact member by said coil, and means for varying the opposition oflered by the re-' leasing means to the actuation of the contact member by the coil.

3. In control apparatus, in combination, a contact member disposed for movement, a coil for actuating the contact member, said coil being adapted to function when energized by a predetermined current, means for locking the contact member in a predetermined position, an electromagnet for releasing the contact member and means for utilizing the electromagnet to oppose the operation of the contact member by the coil.

4. The combination with an overload relay comprising a movable member and a series coil for actuating said member at a predetermined value, of a latching mechanism for said relay, and electro-responsive means for controlling said mechanism, said electroresponsive means energizing a flux path for varying the predetermined value at which said movable member shall be actuated.

5. In a device of the character described for controlling electrical circuits, in combination, a relay operable to effect the making and breaking of circuits, said relay being adapted to operate upon the flow of a predetermined current, means for opposing the operation of the relay to vary the current value at which the relay will operate, said means being variable in efiect thereby to provide for the operation of the relay at different current values, and means for locking the relay in the position assumed when energized.

6. In control apparatus for controlling electrical circuits, in combination, a relay provided with switching means for making and breaking electrical circuits, an armature operated upon the energization of the relay by the flow of a predetermined current, said armature being disposed to operate said switching means, means for locking the switching means in a predetermined position, an electromagnet for releasing said switchmg means, and means for utilizing saidelectromagnet to oppose the operation of the armature to vary the current value at which the relay operates.

7. In control apparatus for controlling electrical circuits, in combination, a relay provided with switching means for making and breaking electrical circuits, an armature operated by the energization of the relay by the flow of a predetermined current,

said armature being disposed to operate said switching means, means for locking the switching means in a predetermined position, an electromagnet for releasing the switching means, and means for utilizing said electromagnet for opposing the operation of the armature to vary the current value at which the relay 0 erates, and means for varying the energizatlon of the electromagnet. I

In testimony whereof, I have hereunto subscribed my name this 13th day of December, 1920,

HOWARD H. JOHNSTON. 

